Check valves have been proposed for use with the fuel filler pipe of automobiles and other vehicles to prevent liquid fuel from flowing back upwardly to the exterior fuel filler port of the vehicle as a result of an increase in fuel tank pressure. One such check valve is described in U.S. Pat. No. 5,327,933 and involves a valve plate that is pivotally mounted on a separate hinge pin at the lower end of the filler pipe communicating with the fuel tank. The valve plate is biased by a separate torsion coil spring disposed on the hinge pin to a closed position relative to the fuel filler pipe. The valve is moved to an open position against bias of the coil spring by liquid fuel introduced into the filler pipe by the usual fuel filler nozzle at a fuel filling station.
Current governmental concerns regarding side impact vehicle collisions may result in adoption of vehicle regulations that require a fuel check valve in the fuel filler pipe in order to prevent liquid fuel escaping from the exterior fuel filler port of the vehicle via the filler pipe during side impact collision testing.
In general, a fuel filler pipe check valve must prevent fuel vapor from flowing out of the fuel tank filler pipe during driving of the vehicle, must prevent liquid fuel from flowing out of the filler pipe during fuel filling, vehicle driving, and vehicle rollover resulting from side impact collisions, and must be openable during filling of the fuel tank to an extent to permit rapid fueling of the tank.
An object of the present invention is to provide a fuel check valve for use with a fuel filler pipe of a vehicle that provides these functions, that is low in cost, and that is simple to manufacture in a mass production environment.